The present invention relates generally to nonimaging optics and more particularly to radiant energy devices used in nonimaging optics.
Nonimaging optics deals with the radiation, concentration, and/or transformation of radiant energy such as light where it is unimportant that an image be produced. In imaging systems, such as telescope systems and camera systems for example, the production of an image is of primary concern. In nonimaging optics, the goal is the transfer, radiation, or concentration of radiant energy such as light with maximum efficiency without regard to the formation of an image. In most if not all nonimaging systems, visually coherent images are not formed. Examples of applications for nonimaging optics include fiber optics, illumination and optical detection, where a primary concern is the efficient transfer of light energy.
Numerous practical situations exist in applied optics wherein it is desirable to perform radiant energy transformations relating to the angular divergence and cross-sectional area of radiant energy emissions such as light beams. Optical power launching and fiber-fiber coupling in optical fiber systems, for example, routinely require such angular transformations of light energy. Similarly, the transformation of a radiative light source into a directional beam of specified spatial intensity and angular divergence is required in many illumination applications.
Of interest to the background of the present invention are nonimaging radiant energy transformation devices such as are illustrated in U.S. Pat. Nos. 4,114,592 and 4,240,692. These devices possess light transmission properties which are superior to imaging devices in terms of efficiency of energy transmission, but they are nonetheless subject to skew ray energy losses. Nonimaging radiant energy devices based on
radiant energy flow lines are disclosed in U.S. Pat. No. 4,237,332. Combinations of such radiant energy devices, in the form of hyperbolically shaped reflectors, with a lens have been proposed as ideal transformers of input energy of any given angle .theta. to an angle of 90 degrees. See, Winston, et al., "Investigations in Non-Imaging Optics: Detection of Faint Sources," Proceedings of the Second Symposium on Energy Engineering Sciences, pp. 110-115 (April 10-11, 1984) and O'Gallagher, et al., "Axially Symmetric Nonimaging Flux Concentrators With the Maximum Theoretical Concentration Ratio," Journal of the Optical Society of America A, Vol. 4, pp. 66-68 (1987).
Despite the above-noted and other developments in the art, there continues to exist a need for energy transducers of novel design which respond to the requirement for highly efficient transformation of, e.g., a light beam of a first acute angular divergence, .theta..sub.1, to a second acute angular divergence, .theta..sub.2, as well as other nonimaging radiant energy devices having desirable characteristics.